Portable To All Linux Distributions.

• New ’envp’ keyword for accessing environment variables. A ‘getenv’ function is provided.
• Now portable to all Linux distributions due to proper PATH enviroment variable being parsed and read.

A new keyword has been added to access the enviroment pointer, just like in C. The ’envp’ keyword pushes a pointer to an array of nul terminated strings onto the stack. It contains all of the enviroment variables passed to the program on It’s creation.

include 'std.stas'

fn main 0 0 {
    "fasm" find_abs_path_of_executable?

    ; (str? len)
    over NULL != assert
		-> 'executable not found'

    ; (str len)
    puts endl
}

So go ahead, try stas!

$ fasm -m 1048576 bootstrap/x86-64_linux.fasm stas
$ ./stas
stas 0.1.1 Copyright (C) 2022  l-m.dev

USAGE: ./stas [OPTIONS] [FILE]

    -o <output>       Specify '-o -' to dump assembly to stdout
    -g                Debug info. Most effective with the `nasm` backend
    -b <backend>      Assemblers `nasm` or `fasm` as compiler backend
    -r                Execute file after compiling. Arguments after this
                      switch will ignored and passed to the program
    -v, --verbose     Activate verbose mode
    --dump-tok        Dump token information after scanning stage
    --dump-ir         Dump intermediate representation after parsing stage
    -h, --help        Show this message

Short Form Function Declarations.

• Short form function declarations for functions that accept and return zero values.

fn main 0 0 {
    ;
}

fn main {
    ;
}

Duplicate String Literals.

• Attempts to merge duplicate string literals. Similar to ‘-fmerge-constants’ in GCC.

fn main {
	"Hello!" drop drop
	"Hello!" drop drop
	"Cello!" drop drop
	"Hello!" drop drop
	"Cello!" drop drop
}

main:
    mov [_rs_p], rsp
    mov rsp, rbp
    mov rbx, _s0
    mov rsi, 6
    mov rbx, _s0
    mov rsi, 6
    mov rbx, _s1
    mov rsi, 6
    mov rbx, _s0
    mov rsi, 6
    mov rbx, _s1
    mov rsi, 6
    mov rbp, rsp
    mov rsp, [_rs_p]
    ret
segment readable
_s0: db "Hello!", 0
_s1: db "Cello!", 0

Rich Error System.

• Rich error system showing and underlining the exact token inside the file that caused the error.
• Bugfix: scanner fixes for multi line character and string literals.
• Bugfix: stack shuffling operations now return correct backtraces in a parser error.

This used to be in the original version of stas. Shortened now to only show one highlighted line, but underlines the offending token in It’s entirety. Changes had to be made to the inner token representation to allow a field that stored It’s length.

1
2
3
4
5
6
7
8
9

fn main {
	"Hello, this is a multi line heredoc string

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do 
eiusmod tempor incididunt ut labore et dolore magna aliqua. Massa 
ultricies mi quis hendrerit dolor........."

	1 2 3 rot
}

1
2
3

fn main {
    unknown_function_call_or_variable
}

Good error reporting in a compiler is very important. It’s extremely useful and allows stas to get right to the point when conveying errors to the programmer.

Seamless Linker Usage

• The linker is now called when generating object files.

When using debug symbols or the NASM backend, the old behavior simply outputted an object file and exits. People will assume that the output of the compiler will be an executable, especially if the output name is set using the ‘-o’ switch.

This is all handled automatically. See this command:

$ ./stas add.stas -b nasm -g -v -o output

Function Attributes.

• Function attributes. ’noreturn’, ‘inline’ and ’noinline’ are supported.

Function attributes are super useful. I use a similar syntax and style to V.

They give extra hints to the stas compiler on certain functions.

- noinline
fn my_noinline_functor {
	2 drop
}

fn main {
	my_noinline_functor
}

main:
        mov [_rs_p], rsp
        mov rsp, rbp
        mov rbx, 2
        mov rbp, rsp
        mov rsp, [_rs_p]
        ret

my_noinline_functor:
        mov [_rs_p], rsp
        mov rsp, rbp
        mov rbx, 2
        mov rbp, rsp
        mov rsp, [_rs_p]
        ret
main:
        mov [_rs_p], rsp
        mov rsp, rbp
        mov rbp, rsp
        mov rsp, [_rs_p]
        call my_noinline_functor
        mov [_rs_p], rsp
        mov rsp, rbp
        mov rbp, rsp
        mov rsp, [_rs_p]
        ret

- inline
fn my_forced_inline {
	2 drop
	2 drop
	2 drop
	2 drop
	2 drop
	2 drop
	2 drop
	2 drop
	2 drop
}

fn main {
	my_forced_inline
}

main:
        mov [_rs_p], rsp
        mov rsp, rbp
        mov rbx, 2
        mov rbx, 2
        mov rbx, 2
        mov rbx, 2
        mov rbx, 2
        mov rbx, 2
        mov rbx, 2
        mov rbx, 2
        mov rbx, 2
        mov rbp, rsp
        mov rsp, [_rs_p]
        ret

Guarentee is the keyword here. If for any reason it cannot, it will throw a compilation error.

- noreturn
fn exit 0 0 {
	
}

fn main {
	exit

	2 3 1
}

Calling a noreturn function, similar to an early return from a function, will push an unreachable scope onto the parsers stack. It will call an ‘unreachable code’ error if any other code is found after it.

Overflow Checks.

• Overflow checks for signed and unsigned integers.

; ( is_negative str len -- bool )
fn does_int_literal_overflow 3 1 {
	auto lit 2 pop lit

	if {
		"9223372036854775808"
	} else {
		"18446744073709551615"
	}

    ......
    ......
    ......

fn main {
	18446744073709551616 drop
}

fn main {
	-9223372036854775809 drop
}

Minor Bugfixes That Make A Major Difference.

• Bugfix: fix early return scopes that caused errors with complex blocks.
• Bugfix: add error for unhandled scope that a complex block requires.
• Bugfix: if and else cases with an early return now are checked correctly in the parser.

These bugfixes fix a ton of bugs relating to parsing branching scopes. Some fix errors with the stack checks done inside the parser and others handling early returns in branches. Good fixes overall.

End.

Time to write some guides.

Goodbye.